|
|
Modification of polymeric substrates by means of non-equilibrium plasma
Kuzminova, Anna ; Kylián, Ondřej (advisor) ; Čech, Vladimír (referee) ; Novák, Stanislav (referee)
Title: Modification of polymeric substrates by means of non-equilibrium plasma Author: Anna Kuzminova Department: Department of Macromolecular Physics Supervisor of the doctoral thesis: doc. RNDr. Ondřej Kylián, Ph.D. Abstract: Processing of polymeric materials by means of non-equilibrium plasma is a topic that reaches increasing attention, which is due to the wide range of possible applications. As an example can be mentioned processing of polymeric foils used for food packaging, where plasma treatment enables to improve their functional properties (e.g. increase their printability or enhance their barrier properties). In the frame of this PhD. thesis two different strategies suitable for the modification of polymeric materials were followed. The first one was based on treatment of polymers by atmospheric plasma. The main attention was devoted to the investigation of influence of atmospheric pressure plasma on surface properties of 8 commonly used polymers, namely on their chemical composition, morphology and wettability. In addition, it was observed that plasma treatment causes also alteration of their mechanical properties, may lead to their substantial etching and in some cases improves their biocompatibility. The second studied strategy was based on coating of polymers with thin functional...
|
|
|
Synchrotron Radiation PhotoElectron Studyof CeOx-Pd,Sn,Au Model Catalysts
Škoda, Michal ; Matolín, Vladimír (advisor) ; Čech, Vladimír (referee) ; Plšek, Jan (referee)
The doctoral thesis deals with study of model catalytic systems Ce(Ox)-Pd(111), Sn-CeO2(111) and Au-CeO2(111). The metal-metal and metal-oxide interactions are investigated by means of photoelectron spectroscopy method (PES), first of all resonant photoelectron spectroscopy (RPES). The RPES method showed, that the chemical state modifications of the system induce significant modifications in the band structure of its atoms implicating dramatic valence band changes. The RPES method has appeared to be a powerful instrument for valence band electron structure study.
|
|
|
Mechanical and Electrical Properties of Microcrystalline Silicon Thin Films
Vetushka, Aliaksei ; Fejfar, Antonín (advisor) ; Čech, Vladimír (referee) ; Sládek, Petr (referee)
Amorphous and nano- or micro- crystalline silicon thin films are intensively studied materials for photovoltaic applications. The films are used as intrinsic layer (absorber) in p-i-n solar cells. As opposed to crystalline silicon solar cells, the thin films contain about hundred times less silicon and can be deposited at much lower temperatures (typically around 200 0 C) which saves energy needed for production and makes it possible to use various low cost (even flexible) substrates. However, these films have a complex microstructure, which makes it difficult to measure and describe the electronic transport of the photogenerated carriers. Yet, the understanding of the structure and electronic properties of the material at nanoscale is essential on the way to improve the efficiency solar cells. One of the main aims of this work is the study of the structure and mechanical properties of the mixed phase silicon thin films of various thicknesses and structures. The key parameter of microcrystalline silicon is the crystallinity, i.e., the microcrys- talline volume fraction. It determines internal structure of the films which, in turn, decides about many other properties, including charge transport and mechanical sta- bility. Raman microspectroscopy is a fast and non-destructive method for probing the...
|
|
| |
|
| |
|
|
Plasma polymers in the nanostructured and nanocomposite coatings
Shelemin, Artem ; Biederman, Hynek (advisor) ; Čech, Vladimír (referee) ; Vyskočil, Jiří (referee)
Title: Plasma polymers in the nanostructured and nanocomposite coatings Author: Artem Shelemin Department / Institute: Department of the Macromolecular Physics Supervisor of the doctoral thesis: Prof. RNDr. Hynek Biederman, DrSc. Abstract: The thesis represents the main results of my research work aimed to study nanostructured and nanocomposite films of plasma polymer. A few alternative experimental approaches were developed and investigated which ranged from low pressure (gas aggregation cluster sources and glancing angle deposition) to atmospheric pressure (dielectric barrier discharge and plasma jet) plasma processing. The metal/metal oxide Ti/TiOx, AlOx and plasma polymer SiOx(CH), Nylon 6,6 nanoparticles were prepared. The analysis of morphology of deposited plasma polymer coatings was performed by AFM and SEM. The chemical composition of films was studied by XPS and FTIR. Keywords: plasma polymer, nanoparticle, thin film, nanostructures
|
|
| |
|
| |
|
|
Preparation of Nanocomposites TiOx /Plasma Polymer and Study of Their Properties
Drábik, Martin ; Biederman, Hynek (advisor) ; Čech, Vladimír (referee) ; Špatenka, Petr (referee)
Title: Preparation of Nanocomposites TiOx/Plasma Polymer and Study of Their Properties Author: Mgr. Martin Drábik Department: Department of Macromolecular Physics Supervisor: Prof. RNDr. Hynek Biederman, DrSc. Supervisor's e-mail address: bieder@kmf.troja.mff.cuni.cz Abstract: This thesis concerns a study of nanocomposite films TiOx/plasma polymer prepared by various deposition techniques using different organic precursors. Processes of deposition of the films were diagnosed in-situ by means of OES and measuring the deposition rate by QCM. Properties of the nanocomposite films were studied by various characterization techniques. Wettability of the films was described by means of the contact angle of water. Morphology of the nanocomposites was characterized by AFM, TEM and SEM. Elemental analysis and chemical composition of the films were studied by XPS, RBS, SIMS and FTIR. Crystal structure of TiO2 films was identified by XRD. Optical characterization of the prepared films was done by UV-Vis spectroscopy. Electrical properties of the samples were characterized by I-V and SPV measurements. In the end, 'wet' chemical processes were utilized for preparation of both TiO2 nanostructures and organic films for comparison with vacuum deposition techniques and plasma polymer composite films. Keywords: nanocomposite...
|
|
| |
guest ::
